While great progress has been made in cancer treatment in the past 30 years, most advances have resulted from empirical therapeutic observations rather than the application of scientific understanding. The purpose of this proposed ICN-UCLA conference is to bring together leading clinical researchers in the primary subdisciplines of cancer treatment (radiotherapy, pharmacology, immunology), with researchers in supporing basic areas, to discuss the scientific basis for the design of tumor-specific cytotoxic therapy. The primary topics for discussion will be: (1) the development of monoclonal antibodies to human tumors and their use in cancer diagnosis and treatment; (2) the molecular basis for steroid hormone action; (3) genetic and molecular bases of antimetabolite resistance; (4) physical targeting of anti-cancer therapy using liposomal encapsulation, heat, and radiation to enhance drug action and improve selectivity of action; and (5) free radical mediated tissue injury. In each case, the basic principles will be discussed in the context of possible or actual application to the clinical treatment of cancer.